.index {
  height: 100vh;
  display: flex;
  justify-content: center;
  align-items: center;
  background-color: #ededed;
}
.circle {
  position: fixed;
  width: 0;
  height: 0;
  border-radius: 60px;
  background-color: orange;
  animation: show 1s;
  animation-fill-mode: forwards;
  z-index: 99;
}

@keyframes show {
  0% {
    width: 50px;
    height: 50px;
    opacity: 1;
  }

  100% {
    width: 50px;
    height: 50px;
    opacity: 0;
    transform: scale(2);
  }
}

.taiji {
  width: 200px;
  height: 200px;
  background: linear-gradient(to bottom, #fff 0%, #fff 50%, #000 50%, #000 100%);
  border-radius: 50%;
  position: relative;
  transition: all 5s linear;
  transform: rotate(0deg);
}
.rotate {
  transition: all 5s linear;
  transform: rotate(360deg);
}
// @keyframes  taiji {
//   0% {
//     transform: rotate(0);
//   }
//   100% {
//     transform: rotate(360deg);
//   }
// }

.taiji .white {
  width: 100px;
  height: 100px;
  position: absolute;
  box-sizing: border-box;
  background-color: #fff;
  border-radius: 50%;
  margin-top: 10px;
  left: 0;
  top: 45px;
  border: 40px solid #000;
}

.taiji .black {
  width: 100px;
  height: 100px;
  position: absolute;
  box-sizing: border-box;
  background-color: #000;
  border-radius: 50%;
  right: 0;
  top: 45px;
  border: 40px solid #fff;
}
.btn {
  margin: 16px;
}
.opac {
  opacity: 0;
  --rotate: 1;
}